Refactor: Move RAG components to dedicated top-level module (#3222)

* Move RAG components to top-level module

- Create src/crewai/rag directory structure
- Move embeddings configurator from utilities to rag module
- Update imports across codebase and documentation
- Remove deprecated embedding files

* Remove empty knowledge/embedder directory

src/crewai/utilities/__init__.py

@@ -10,7 +10,6 @@ from .rpm_controller import RPMController
 from .exceptions.context_window_exceeding_exception import (
     LLMContextLengthExceededException,
 )
-from .embedding_configurator import EmbeddingConfigurator
 
 __all__ = [
     "Converter",
@@ -24,5 +23,4 @@ __all__ = [
     "RPMController",
     "YamlParser",
     "LLMContextLengthExceededException",
-    "EmbeddingConfigurator",
 ]